A common procedure in medical practice is the insertion of a surgical cannula in a blood vessel of a patient for the purpose of monitoring blood pressure, obtaining blood samples, introducing medicinal dosages, or the like.
It is often difficult and tedious to locate and puncture a blood vessel of a patient who is in hypotension, or is obese and the blood vessel is not close to the skin surface, or the patient is elderly and the blood vessel is thickened and tends to displace during the cannulation procedure.
Various cannulation devices have been proposed for improving venipuncture procedures to ease inherent difficulties of the type noted above. Of particular interest with respect to the present invention are devices which utilize an ultrasonic probe and cannula guide means. Pertinent references include U.S. Pat. Nos. 4,029,084; 4,289,139; 4,387,721; and 4,667,679. Accurate guiding of a cannula relative to the blood vessel located by the ultrasonic probe is not easily accomplished with the type of cannulation devices described in the prior art.
There remains a need for new and improved devices to overcome the various difficulties associated with cannulation of blood vessels in patients.
Accordingly, it is an object of this invention to provide a cannulation device which has ultrasonic probe means and cannula guide means for locating and puncturing of blood vessels.
It is a further object of this invention to provide a cannulation device which locates a blood vessel ultrasonically and guides a puncturing cannula with ease and precision.
Other objects and advantages of the present invention shall become apparent from the accompanying description and drawings.